1. Field of the Invention
The present invention relates to a gas-flow exhaust assembly for a jet propulsion system of an aircraft. More specifically, it relates to an exhaust assembly comprising a primary duct through which a primary gas flow passes during operation of the jet propulsion system and which terminates in a converging, primary exhaust nozzle at a downstream end thereof. The primary exhaust nozzle comprises two half-clamshells constituting hot flaps which hinge on horizontal transverse shafts. The primary exhaust nozzle transitions in shape from a nozzle intake cross-section matching the primary duct to a nozzle exhaust cross-section having a substantially elliptical or rectangular overall shape. A first control mechanism is arranged to drive the hot flaps. The primary exhaust nozzle is also fitted with a fairing which forms a rear end of the aircraft and encloses the primary duct.
2. Description of the Related Art
Such an exhaust assembly is described in French patent 2,740,833. The convergent primary exhaust nozzle allows flattening of the jet of hot gases at the engine exhaust to reduce the infrared signature.
In French patent 2,740,833, the fairing forming the rear end of the aircraft extends rearward beyond the outlet of the primary exhaust nozzle and assures aerodynamic continuity of the aircraft. This stationary fairing is in the form of a converging/diverging secondary exhaust nozzle of fixed cross-section.
Presently missiles, in particular those guided by infrared and radars, used on military aircraft have become increasingly perfected with respect to detection, guidance and destructiveness.
This increasing sophistication in missile and radar design therefore demands that aircraft and engine designers for the armed forces provide not only high-performance products, but also products having high manoeuverability and stealth. The stealth requirement demands further reduction of the engine's infrared signature.